UPDATE
    cohort_item
SET
    name = sub.name
FROM ( WITH from_cohort_item AS (
        SELECT
            ci.pack_size,
            CASE WHEN LENGTH(cib.barcode) = 12 THEN
                SUBSTRING(cib.barcode, 2, 10)
            WHEN LENGTH(cib.barcode) = 8 THEN
                SUBSTRING(cib.barcode, 2, 6)
            ELSE
                cib.barcode
            END AS barcode,
            ci.name
        FROM
            cohort_item ci
            JOIN cohort_item_barcode cib ON ci.id = cib.cohort_item_id
        WHERE
            ci.cohort_id = @source_cohort_id),
        to_cohort_item AS (
            SELECT
                ci.pack_size,
                CASE WHEN LENGTH(cib.barcode) = 12 THEN
                    SUBSTRING(cib.barcode, 2, 10)
                WHEN LENGTH(cib.barcode) = 8 THEN
                    SUBSTRING(cib.barcode, 2, 6)
                ELSE
                    cib.barcode
                END AS barcode,
                ci.id AS cohort_item_id,
                ci.cohort_id
            FROM
                cohort_item ci
                JOIN cohort_item_barcode cib ON ci.id = cib.cohort_item_id
            WHERE
                ci.cohort_id = @target_cohort_id
)
            SELECT DISTINCT
                tci.cohort_item_id,
                fci.name
            FROM
                from_cohort_item fci
                JOIN to_cohort_item tci ON tci.barcode = fci.barcode
                    AND fci.pack_size = tci.pack_size) AS sub
WHERE
    cohort_item.id = sub.cohort_item_id
    AND cohort_item.name <> sub.name
    AND cohort_item.cohort_id = @target_cohort_id;